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<h1>Configuration Options</h1>
<p>There are many options to configure the functions of FatFs for requirement of each project. The configuration options are defined in the <em><tt>ffconf.h</tt></em>.</p>
<ul>
<li>Function Configurations
 <ul>
   <li><a href="#fs_readonly">FF_FS_READONLY</a></li>
   <li><a href="#fs_minimize">FF_FS_MINIMIZE</a></li>
   <li><a href="#use_find">FF_USE_FIND</a></li>
   <li><a href="#use_mkfs">FF_USE_MKFS</a></li>
   <li><a href="#use_fastseek">FF_USE_FASTSEEK</a></li>
   <li><a href="#use_expand">FF_USE_EXPAND</a></li>
   <li><a href="#use_chmod">FF_USE_CHMOD</a></li>
   <li><a href="#use_label">FF_USE_LABEL</a></li>
   <li><a href="#use_forward">FF_USE_FORWARD</a></li>
   <li><a href="#use_strfunc">FF_USE_STRFUNC</a></li>
   <li><a href="#print_lli">FF_PRINT_LLI</a></li>
   <li><a href="#print_fp">FF_PRINT_FLOAT</a></li>
   <li><a href="#strf_encode">FF_STRF_ENCODE</a></li>
 </ul>
</li>
<li>Namespace and Locale Configurations
 <ul>
   <li><a href="#code_page">FF_CODE_PAGE</a></li>
   <li><a href="#use_lfn">FF_USE_LFN</a></li>
   <li><a href="#max_lfn">FF_MAX_LFN</a></li>
   <li><a href="#lfn_unicode">FF_LFN_UNICODE</a></li>
   <li><a href="#lfn_buf">FF_LFN_BUF, FF_SFN_BUF</a></li>
   <li><a href="#fs_rpath">FF_FS_RPATH</a></li>
 </ul>
</li>
<li>Volume/Drive Configurations
 <ul>
   <li><a href="#volumes">FF_VOLUMES</a></li>
   <li><a href="#str_volume_id">FF_STR_VOLUME_ID</a></li>
   <li><a href="#volume_strs">FF_VOLUME_STRS</a></li>
   <li><a href="#multi_partition">FF_MULTI_PARTITION</a></li>
   <li><a href="#max_ss">FF_MIN_SS, FF_MAX_SS</a></li>
   <li><a href="#fs_lba64">FF_LBA64</a></li>
   <li><a href="#fs_gptmin">FF_GPT_MIN</a></li>
   <li><a href="#use_trim">FF_USE_TRIM</a></li>
 </ul>
</li>
<li>System Configurations
 <ul>
   <li><a href="#fs_tiny">FF_FS_TINY</a></li>
   <li><a href="#fs_exfat">FF_FS_EXFAT</a></li>
   <li><a href="#fs_nortc">FF_FS_NORTC</a></li>
   <li><a href="#nortc_time">FF_NORTC_MON, FF_NORTC_MDAY, FF_NORTC_YEAR</a></li>
   <li><a href="#fs_nofsinfo">FF_FS_NOFSINFO</a></li>
   <li><a href="#fs_lock">FF_FS_LOCK</a></li>
   <li><a href="#fs_reentrant">FF_FS_REENTRANT</a></li>
   <li><a href="#fs_timeout">FF_FS_TIMEOUT</a></li>
   <li><a href="#sync_t">FF_SYNC_t</a></li>
 </ul>
</li>
</ul>

<div class="para doc" id="func">
<h3>Function Configurations</h3>

<h4 id="fs_readonly">FF_FS_READONLY</h4>
<p>Read/Write (0) or Read-only (1). Read-only configuration removes writing API functions, <tt>f_write</tt>, <tt>f_sync</tt>, <tt>f_unlink</tt>, <tt>f_mkdir</tt>, <tt>f_chmod</tt>, <tt>f_rename</tt>, <tt>f_truncate</tt>, <tt>f_getfree</tt> and optional writing functions as well.</p>

<h4 id="fs_minimize">FF_FS_MINIMIZE</h4>
<p>This option defines minimization level to remove some basic API functions as follows:</p>
<table class="lst1">
<tr><th>Value</th><th>Description</th></tr>
<tr><td>0</td><td>All basic API functions are available.</td></tr>
<tr><td>1</td><td><tt>f_stat</tt>, <tt>f_getfree</tt>, <tt>f_unlink</tt>, <tt>f_mkdir</tt>, <tt>f_chmod</tt>, <tt>f_utime</tt>, <tt>f_truncate</tt> and <tt>f_rename</tt> function are removed.</td></tr>
<tr><td>2</td><td><tt>f_opendir</tt>, <tt>f_readdir</tt> and <tt>f_closedir</tt> function are removed in addition to 1.</td></tr>
<tr><td>3</td><td><tt>f_lseek</tt> function is removed in addition to 2.</td></tr>
</table>

<h4 id="use_find">FF_USE_FIND</h4>
<p>Disable (0) or Enable (1) filtered directory read functions, <tt>f_findfirst</tt> and <tt>f_findnext</tt>. Also <tt>FF_FS_MINIMIZE</tt> needs to be 0 or 1.</p>

<h4 id="use_mkfs">FF_USE_MKFS</h4>
<p>Disable (0) or Enable (1) <tt>f_mkfs</tt> function.</p>

<h4 id="use_fastseek">FF_USE_FASTSEEK</h4>
<p>Disable (0) or Enable (1) fast seek function to enable accelerated mode for <tt>f_lseek</tt>, <tt>f_read</tt> and <tt>f_write</tt> function. For more information, read <a href="lseek.html">here</a>.</p>

<h4 id="use_expand">FF_USE_EXPAND</h4>
<p>Disable (0) or Enable (1) <tt>f_expand</tt> function.</p>

<h4 id="use_chmod">FF_USE_CHMOD</h4>
<p>Disable (0) or Enable (1) metadata control functions, <tt>f_chmod</tt> and <tt>f_utime</tt>. Also <tt>FF_FS_READONLY</tt> needs to be 0.</p>

<h4 id="use_label">FF_USE_LABEL</h4>
<p>Disable (0) or Enable (1) API functions for volume label, <tt>f_getlabel</tt> and <tt>f_setlabel</tt>.</p>

<h4 id="use_forward">FF_USE_FORWARD</h4>
<p>Disable (0) or Enable (1) <tt>f_forward</tt> function.</p>

<h4 id="use_strfunc">FF_USE_STRFUNC</h4>
<p>This option switches string functions, <tt>f_gets</tt>, <tt>f_putc</tt>, <tt>f_puts</tt> and <tt>f_printf</tt>. These functions are equivalents of regular string stream I/O functions in POSIX. If <tt>sprintf</tt> is available and code conversion is not needed, <tt>f_write</tt> with <tt>sprintf</tt> will be efficient in code size and performance rather than <tt>f_printf</tt>.</p>
<table class="lst1">
<tr><th>Value</th><th>Description</th></tr>
<tr><td>0</td><td>Disable string functions.</td></tr>
<tr><td>1</td><td>Enable string functions without LF-CRLF conversion.</td></tr>
<tr><td>2</td><td>Enable string functions with LF-CRLF conversion.</td></tr>
</table>

<h4 id="print_lli">FF_PRINT_LLI</h4>
<p>This option switches support for long long integer argument in <tt>f_printf</tt>.</p>
<p>Disable (0) or Enable (1). C standard needs to be C99 or later to enable this feature.</p>

<h4 id="print_fp">FF_PRINT_FLOAT</h4>
<p>This option switches support for floating point argument in <tt>f_printf</tt>. C standard needs to be C99 or later to enable this feature.</p>
<table class="lst1">
<tr><th>Value</th><th>Description</th></tr>
<tr><td>0</td><td>Disable floating point argument.</td></tr>
<tr><td>1</td><td>Enable floating point argument in type <tt>'f'</tt>, <tt>'e'</tt> and <tt>'E'</tt>.</td></tr>
<tr><td>2</td><td>Enable with decimal separator <tt>','</tt> instead of <tt>'.'</tt>.</td></tr>
</table>

<h4 id="strf_encode">FF_STRF_ENCODE</h4>
<p>When character encoding on the API is Unicode (<tt>FF_LFN_UNICODE &gt;= 1</tt>), string I/O functions enabled by <tt>FF_USE_STRFUNC</tt> convert the character encoding in it. This option defines the assumption of character encoding <em>on the file</em> to be read/written via those functions. When LFN is not enabled or <tt>FF_LFN_UNICODE == 0</tt>, the string functions work without any code conversion and this option has no effect.</p>
<table class="lst2">
<tr><th>Value</th><th>Character encoding on the file</th></tr>
<tr><td>0</td><td>ANSI/OEM in current code page</td></tr>
<tr><td>1</td><td>Unicode in UTF-16LE</td></tr>
<tr><td>2</td><td>Unicode in UTF-16BE</td></tr>
<tr><td>3</td><td>Unicode in UTF-8</td></tr>
</table>

</div>


<div class="para doc" id="name">
<h3>Namespace and Locale Configurations</h3>

<h4 id="code_page">FF_CODE_PAGE</h4>
<p>This option specifies the OEM code page used on the target system. Incorrect setting of the code page can cause a file open failure. If any non-ASCII character is not used for the path name or <tt>FF_LFN_UNICODE != 0</tt>, there is no difference between any code page settings. Set it 437 anyway.</p>
<table class="lst1">
<tr><th>Value</th><th>Code page</th></tr>
<tr><td>0</td><td>Includes all code pages below and set by <tt>f_setcp()</tt></td></tr>
<tr><td>437</td><td>U.S.</td></tr>
<tr><td>720</td><td>Arabic</td></tr>
<tr><td>737</td><td>Greek</td></tr>
<tr><td>771</td><td>KBL</td></tr>
<tr><td>775</td><td>Baltic</td></tr>
<tr><td>850</td><td>Latin 1</td></tr>
<tr><td>852</td><td>Latin 2</td></tr>
<tr><td>855</td><td>Cyrillic</td></tr>
<tr><td>857</td><td>Turkish</td></tr>
<tr><td>860</td><td>Portuguese</td></tr>
<tr><td>861</td><td>Icelandic</td></tr>
<tr><td>862</td><td>Hebrew</td></tr>
<tr><td>863</td><td>Canadian French</td></tr>
<tr><td>864</td><td>Arabic</td></tr>
<tr><td>865</td><td>Nordic</td></tr>
<tr><td>866</td><td>Russian</td></tr>
<tr><td>869</td><td>Greek 2</td></tr>
<tr><td>932</td><td>Japanese (DBCS)</td></tr>
<tr><td>936</td><td>Simplified Chinese (DBCS)</td></tr>
<tr><td>949</td><td>Korean (DBCS)</td></tr>
<tr><td>950</td><td>Traditional Chinese (DBCS)</td></tr>
</table>

<h4 id="use_lfn">FF_USE_LFN</h4>
<p>This option switches the support for long file name (LFN). When enable the LFN, Unicode support module <tt>ffunicode.c</tt> need to be added to the project. When use stack for the working buffer, take care on stack overflow. When use heap memory for the working buffer, memory management functions (<tt>ff_memalloc</tt> and <tt>ff_memfree</tt>) need to be added to the project.</p>
<table class="lst1">
<tr><th>Value</th><th>Description</th></tr>
<tr><td>0</td><td>Disable LFN. Path name in only 8.3 format can be used.</td></tr>
<tr><td>1</td><td>Enable LFN with static working buffer on the BSS. Always NOT thread-safe.</td></tr>
<tr><td>2</td><td>Enable LFN with dynamic working buffer on the STACK.</td></tr>
<tr><td>3</td><td>Enable LFN with dynamic working buffer on the HEAP.</td></tr>
</table>

<h4 id="max_lfn">FF_MAX_LFN</h4>
<p>LFN function requiers certain internal working buffer for the file name. This option defines size of the buffer and the value can be in range of 12 to 255 characters (actually in UTF-16 code units) of the LFN. The buffer occupies <tt>(FF_MAX_LFN + 1) * 2</tt> bytes and additional <tt>(FF_MAX_LFN + 44) / 15 * 32</tt> bytes when exFAT is enabled. It is recommended to be set 255 to fully support the LFN specification. This option has no effect when LFN is not enabled.</p>

<h4 id="lfn_unicode">FF_LFN_UNICODE</h4>
<p>This option switches character encoding for the file name on the API. FatFs supports the code point up to U+10FFFF. This option also affects behavior of string I/O functions (see <tt>FF_STRF_ENCODE</tt>).</p>
<table class="lst2">
<tr><th>Value</th><th>Character Encoding</th><th><tt>TCHAR</tt></th></tr>
<tr><td>0</td><td>ANSI/OEM in current CP</td><td>char</td></tr>
<tr><td>1</td><td>Unicode in UTF-16</td><td>WCHAR</td></tr>
<tr><td>2</td><td>Unicode in UTF-8</td><td>char</td></tr>
<tr><td>3</td><td>Unicode in UTF-32</td><td>DWORD</td></tr>
</table>
<p>When Unicode is selected, <tt>FF_CODE_PAGE</tt> has actually no meaning except for compatibility with legacy systems, such as MS-DOS and any system without support for LFN.</p>
<p>When LFN is not enabled, this option has no effect and FatFs works in ANSI/OEM code on the API. For more information, read <a href="filename.html#uni">here</a>.</p>

<h4 id="lfn_buf">FF_LFN_BUF, FF_SFN_BUF</h4>
<p>This set of options defines size of file name members, <tt>fname[]</tt> and <tt>altname[]</tt>, in the <tt><a href="sfileinfo.html">FILINFO</a></tt> structure which is used to read out the directory items. These values should be suffcient for the file names to read. The maximum possible length of read file name depends on the character encoding scheme on the API as follows:</p>
<table class="lst2">
<tr><th>Encoding</th><th>LFN length</th><th>SFN length</th></tr>
<tr><td>ANSI/OEM in SBCS</td><td>255 items</td><td>12 items</td></tr>
<tr><td>ANSI/OEM in DBCS</td><td>510 items</td><td>12 items</td></tr>
<tr><td>Unicode in UTF-16/32</td><td>255 items</td><td>12 items</td></tr>
<tr><td>Unicode in UTF-8</td><td>765 items</td><td>34 items</td></tr>
</table>
<p>If the size of name member is insufficient for the LFN, the item is treated as without LFN. When LFN is not enabled, these options have no effect.</p>

<h4 id="fs_rpath">FF_FS_RPATH</h4>
<p>This option configures relative path function. For more information, read <a href="filename.html#nam">here</a>.</p>
<table class="lst1">
<tr><th>Value</th><th>Description</th></tr>
<tr><td>0</td><td>Disable relative path function and remove related functions.</td></tr>
<tr><td>1</td><td>Enable relative path function. <tt>f_chdir</tt> and <tt>f_chdrive</tt> function is available.</td></tr>
<tr><td>2</td><td><tt>f_getcwd</tt> function is available in addition to 1</td></tr>
</table>

</div>


<div class="para doc" id="volume">
<h3>Volume/Drive Configurations</h3>

<h4 id="volumes">FF_VOLUMES</h4>
<p>This option configures number of volumes (logical drives up to 10) to be used.</p>

<h4 id="str_volume_id">FF_STR_VOLUME_ID</h4>
<p>This option switches the support for string volume ID. When arbitrary string for the volume ID is enabled for the drive prefix, also pre-defined strings by <tt>FF_VOLUME_STRS</tt> or user defined strings can be used as drive prefix in the path name. Numeric drive number is always valid regardless of this option, and also either format of drive prefix can be enabled by this option.</p>
<table class="lst2">
<tr><th>Value</th><th>Description</th><th>Example</th></tr>
<tr><td>0</td><td>Only DOS/Windows style drive prefix in numeric ID can be used.</td><td>1:/filename</td></tr>
<tr><td>1</td><td>Also DOS/Windows style drive prefix in string ID can be used.</td><td>flash:/filename</td></tr>
<tr><td>2</td><td>Also Unix style drive prefix in string ID can be used.</td><td>/flash/filename</td></tr>
</table>

<h4 id="volume_strs">FF_VOLUME_STRS</h4>
<p>This option defines the volume ID strings for each logical drives. Number of items must not be less than <tt>FF_VOLUMES</tt>. Valid characters for the volume ID string are A-Z, a-z and 0-9, however, they are compared in case-insensitive. If <tt>FF_STR_VOLUME_ID == 0</tt>, this option has no effect. If <tt>FF_STR_VOLUME_ID &gt;= 1</tt> and this option is not defined, a user defined volume string table needs to be defined as shown below. The table should not be modified on the fly.</p>
<pre>
<span class="c">/* User defined volume ID strings for 0: to 3: */</span>
const char* VolumeStr[FF_VOLUMES] = {"ram","flash","sd","usb"};
</pre>

<h4 id="multi_partition">FF_MULTI_PARTITION</h4>
<p>Disable (0) or Enable (1). This option switches multi-partition function. By default (0), each logical drive number is bound to the same physical drive number and only a volume in the physical drive is mounted. When enabled, each logical drive is bound to the partition on the physical drive listed in the user defined partition resolution table <tt>VolToPart[]</tt>. Also <tt>f_fdisk</tt> funciton will be available. For more information, read <a href="filename.html#vol">here</a>.</p>

<h4 id="max_ss">FF_MIN_SS, FF_MAX_SS</h4>
<p>This set of options defines the extent of sector size used for the low level disk I/O interface, <tt>disk_read</tt> and <tt>disk_write</tt> function. Valid values are 512, 1024, 2048 and 4096. <tt>FF_MIN_SS</tt> defines minimum sector size and <tt>FF_MAX_SS</tt> defines the maximum sector size. Always set both 512 for memory card and harddisk. But a larger value may be required for on-board flash memory and some type of optical media. When <tt>FF_MAX_SS &gt; FF_MIN_SS</tt>, support of variable sector size is enabled and <tt>GET_SECTOR_SIZE</tt> command needs to be implemented to the <tt>disk_ioctl</tt> function.</p>

<h4 id="fs_lba64">FF_LBA64</h4>
<p>This option switches media access interface to 64-bit LBA and enables GUID Partition Table (GPT) for partition management, Enabled (1) or Disabled (0). exFAT filesystem needs to be enabled to enable this feature.</p>

<h4 id="fs_gptmin">FF_MIN_GPT</h4>
<p>This option specifies the threshold of determination of partitioning format when create patitions on the drive in <tt>f_mkfs</tt> and <tt>f_fdisk</tt> function. When number of sectors on the drive is equal or larger than this value, the drive will be partitioned in GPT. This option has no effect when <tt>FF_LBA64 == 0</tt>.</p>

<h4 id="use_trim">FF_USE_TRIM</h4>
<p>Disable (0) or Enable (1). This option switches ATA-TRIM function. To enable Trim function, also <tt>CTRL_TRIM</tt> command should be implemented to the <tt>disk_ioctl</tt> function.</p>

</div>


<div class="para doc" id="system">
<h3>System Configurations</h3>

<h4 id="fs_tiny">FF_FS_TINY</h4>
<p>Normal (0) or Tiny (1). The tiny configuration reduces size of the <tt>FIL</tt> structure, file object, <tt>FF_MAX_SS</tt> bytes each. Instead of private sector buffer eliminated from the file object, common sector buffer in the <tt>FATFS</tt> structure, filesystem object, is used for the file data transfer.</p>

<h4 id="fs_exfat">FF_FS_EXFAT</h4>
<p>This option switches support for exFAT filesystem in addition to the FAT/FAT32 filesystem, Enabled (1) or Disabled (0). To enable exFAT, also LFN must be enabled and configureing <tt>FF_LFN_UNICODE &gt;= 1</tt> and <tt>FF_MAX_LFN == 255</tt> is recommended for full-featured exFAT function. Note that enabling exFAT discards ANSI C (C89) compatibility and wants C99 because of need for 64-bit integer type.</p>

<h4 id="fs_nortc">FF_FS_NORTC</h4>
<p>Use RTC (0) or Do not use RTC (1). This option controls timestamp function. If the system does not have any RTC function or valid timestamp is not needed, set <tt>FF_FS_NORTC</tt> to 1 to disable the timestamp function. Every objects modified by FatFs will have a fixed timestamp defined by <tt>FF_NORTC_MON</tt>, <tt>FF_NORTC_MDAY</tt> and <tt>FF_NORTC_YEAR</tt>. To use the timestamp function, set <tt>FF_FS_NORTC == 0</tt> and add <tt>get_fattime</tt> function to the project to get current time form the RTC. This option has no effect in read-only configuration.</p>

<h4 id="nortc_time">FF_NORTC_MON, FF_NORTC_MDAY, FF_NORTC_YEAR</h4>
<p>This set of options defines the time to be used in no RTC systems. This option has no effect in read-only configuration or <tt>FF_FS_NORTC == 0</tt>.</p>

<h4 id="fs_nofsinfo">FF_FS_NOFSINFO</h4>
<p>0 to 3. If you need to know correct free space on the FAT32 volume, set bit 0 of this option, and <tt>f_getfree</tt> function at first time after volume mount will force a full FAT scan. Bit 1 controls the use of last allocated cluster number for new allocation.</p>
<table class="lst1">
<tr><th>Value</th><th>Description</th></tr>
<tr><td>bit0=0</td><td>Use free cluster count in the FSINFO if available.</td></tr>
<tr><td>bit0=1</td><td>Do not trust free cluster count in the FSINFO.</td></tr>
<tr><td>bit1=0</td><td>Use last allocated cluster number in the FSINFO to find a free cluster if available.</td></tr>
<tr><td>bit1=1</td><td>Do not trust last allocated cluster number in the FSINFO.</td></tr>
</table>

<h4 id="fs_lock">FF_FS_LOCK</h4>
<p>This option switches file lock function to control duplicated file open and illegal operations to open objects. Note that the file lock function is independent of re-entrancy. This option must be 0 in read-only configuration.</p>
<table class="lst1">
<tr><th>Value</th><th>Description</th></tr>
<tr><td>0</td><td>Disable file lock function. To avoid collapsing file by wrong file operation, application program needs to avoid illegal open, remove and rename to the open objects.</td></tr>
<tr><td>&gt;0</td><td>Enable file lock function. The value defines how many files/sub-directories can be opened simultaneously under the file lock control. Illigal operations to the open object will be rejected with <tt>FR_LOCKED</tt>.</td></tr>
</table>

<h4 id="fs_reentrant">FF_FS_REENTRANT</h4>
<p>Disable (0) or Enable (1). This option switches the re-entrancy (thread safe) of the FatFs module itself. Note that file/directory access to the different volume is always re-entrant and it can work simultaneously regardless of this option, however, volume management functions, <tt>f_mount</tt>, <tt>f_mkfs</tt> and <tt>f_fdisk</tt>, are always not re-entrant. Only file/directory access to the same volume, in other words, exclusive use of each filesystem object, is under control of this function. To enable this feature, also user provided synchronization handlers, <tt>ff_req_grant</tt>, <tt>ff_rel_grant</tt>, <tt>ff_del_syncobj</tt> and <tt>ff_cre_syncobj</tt>, need to be added to the project. Sample code is available in <tt>ffsystem.c</tt>.</p>

<h4 id="fs_timeout">FF_FS_TIMEOUT</h4>
<p>Number of time ticks to abort the file function with <tt>FR_TIMEOUT</tt> when wait time is too long. This option has no effect when <tt>FF_FS_REENTRANT == 0</tt>.</p>

<h4 id="sync_t">FF_SYNC_t</h4>
<p>This option defines O/S dependent sync object type. e.g. <tt>HANDLE</tt>, <tt>ID</tt>, <tt>OS_EVENT*</tt>, <tt>SemaphoreHandle_t</tt> and etc. A header file for O/S definitions needs to be included somewhere in the scope of <tt>ff.c</tt>. This option has no effect when <tt>FF_FS_REENTRANT == 0</tt>.</p>

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